Dasya ballantinei Huisman

Scientific Description

Habit and structure. Thallus to 15 mm tall, lightly corticated in lower portions; primary axes to 300 µm diam., with 5 pericentral cells. Pseudolaterals arising on each segment in a radial pattern at apices prior to periaxial cell formation, dichotomously divided with 1 or 2 cells between dichotomies, typically unequal with each pair comprised of a 1-celled branch and a 2-celled branch; lower cells to 35 µm diam. Periaxial cells each cutting off basipetally a small cell that fuses with the periaxial cell of the adjacent segment, resulting in secondary pit connections, and a similar cell acropetally from the periaxial proximal to the basal cell of the pseudolateral, also resulting in a secondary pit connection. Basipetal corticating filaments arising from basal cells of pseudolaterals.

Reproduction. Tetrasporangial stichidia with 1–4-celled pedicels, 600–700 µm long and 100–130 µm diam., with whorls of 5 tetrahedrally divided tetrasporangia per segment (4 in lowermost segment), the fertile periaxial cells also cutting off 3 post-sporangial cover cells per tetrasporangium, these projecting proximally as well as distally and slightly covering the sporangium on the segment below as well as the sporangium on the bearing cell. Cover cells longitudinally elongate, slightly narrowed medially. Tetrasporangia spherical, 40–50 µm diam., tetrahedrally divided. Other reproductive structures not seen.

Distribution. Known from Barrow Island north to the Maret Islands, north-western Australia.

Habitat. Epiphytic in the intertidal and shallow subtidal.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 424–426 (2018)]